SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cb7a7de0d4c3d78d3bad91cd2cf4b7eab1ef4cafe0059d88b7d06ec5bb7a125e' 
  AND token = 'F5hWBMgPllk0LqpdTXpP2nF71dzYu65QKZPPAu5Tzl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}